Cellulose acetate composition



an acetic acid content Patented June 26, 1945 UNITED STATES PATENTOFFICE 4 zsiaoss- OELLULOSE ACETATE comrosrnos Frank E. Piecli,Sayreville, N. J.,. asslgnor to Hercules Powder Company, Wilmington,DeL, a corporation of Delaware No Drawing. Application November 26,1942, Serial No. 467,080

Claims. ('01. 106-179) This invention relates to compositions of matterin which cellulose acetate is combined with other substances such ascompatible plasticizers and, more particularly, to compositions ofmatter in which cellulose acetate is combined on mixing with a solventplasticizer and certain phenoxy ethanols.

It is well known that in the production 01' sheets, films, moldingpowder, molded products, varnishes, lacquers, etc., it is necessary tocomblue or mix cellulose acetate with certain plasticizers in order toobtain products of desirable hardness, flexibility, etc. Particularly inthe molding of articles, it is desirable that plasticizers be added tolower the temperature at which the cellulose acetate may be molded aswell as to produce a product which is nonbrittle. I j

There are a large number of desirable plasticizers known to the art forthe purpose of plasticizing cellulose acetate compositions but many ofthem are expensive or not obtainable under wartime conditions. Dimethylphthalate has I beeniound particularly desirable as a plasticizer forcellulose acetate but a relatively large amount of it is required toplasticize properly and the material is not always obtainable.

Now, in accordance with the present invention, it has been discoveredthat cellulose acetate may be desirably plasticized by the use ofparatertiary phenoxy ethanols admixed with other solvent plasticizers.In this manner, phenoxy ethanols may be substituted for a part of thesolvent plasticizer formerly used.

The following are examples of methods oi carrying out this invention:

. E ample 1 Seventy-two parts a viscosity of from 30 to 60 seconds werecolloided with 14 parts of para-tertiary amyl phenoxy. ethanol and 14parts of dimethyl phthalatei; T he material was cast in the form of asheet which had desirable plastic properties.

Example 2 Sixty-nine parts of cellulose acetate having an acetic acidcontent of from 52.5 to 53.5% and a viscosity of from 30 to 60 secondswere col loided with 15.5 parts of para-tertiary amyl phenoxy ethanoland 15.5 parts 01' dimethyl phthalate in the presence of an80-20acetonealcohol mixture. The composition was milled. cut'into moldingpowder,

these and molded in the form of a comb. The product had a hardness,Rockwell "M" 01' 62 and was flexible.

Example 3 Sixty-nine parts of cellulose acetate having an acetic acidcontent between 55.5 and 56.2%

i cellulose acetate having Y of from 52.5 to 63.5% and dried free oisolvent 88 M! and a viscosity of from 35 to seconds were mixed with 15.5parts of para-tertiary amyl phenoxy ethanol and 15.5 parts oi dimethylphthalate. The mixture was cast in the form 01" a sheet which was foundto be flexible.

Example 4 Sixty-nine parts of cellulose acetate having an acetic acidcontent of from 52.5 to 53.5% and a viscosity of from 30 to seconds weremixed. with 15.5 parts of para-tertiary butyl phenoxy ethanol and 15.5parts of dimethyl phthalate. The mixture was colloided using an -20acetone-alcohol solvent. The colloided material was extruded and cutinto the form of molding powder. The molding powder was molded underincreased temperature and pressure in the form oi a comb which had ahardness Rockwell M of and was flexible.

Example 5 Sixty-nine parts of ceilulo acetate having an acetic acidcontent of from .5 to 57.5% and a viscosity of to seconds were mixedwith 15.5 parts of para-tertiary butyl phenoxy ethanol and 15.5 parts ofdimethyhphthalate. The mixture was cast in the form of a sheet which wasflexible.

Example 6 n/ Sixty-nine parts of cellulose acetate having an acetic acidcontent of from 52.5 to 53.5% and a ethanol, para-tertiary butylphenoxyl ethanol, Dara-tertiary butyl phenoxy and the ester,

para-tert ary amyl phenoxy" Various types of solvent plasticizers areknown and those which have been found particularly useful includedibutyl tartrate, diethyl phthalate,

ethyl p-toluene sulfonamid, methyl phthalyl ethyl glycollate, methylcellosolve phthalate, triacetin, and tributyl phosphate.

The para-tertiary alkyl phenoxy ethanols in combination with a solventplasticizer have been found useful with a wide range of aceticacidcontent cellulose acetate but, in general, have been foundparticularly useful in the range of 52% to 57% acetic acid content whenthe product is to be a plastic and from 55% to 57% acetic acid contentwhen the product is a illm. The viscosity ranges of the celluloseacetate may vary buti,s in general, will fall between and 140 secon Therelationship between the para-tertiary alkyl phenoxy ethanol and thesolvent plasticizer may be varied over a wide range but a relationshipof 1 part of solvent plasticizer, such as dimethyl phthalate, to 1 partof the para-tertiary alkyl phenoxy ethanol has been found mostdesirable. For best results, 1 part of solvent plasticizer to not morethan 3 parts phenoxy-ethanol should be used.

The total percentage of plasticizer to celluloseacetate may also bevaried widely depending on the product that is to be manufactured but,in general, a content of'from 30 to 60% of pissticizer will be. used inthe forming oi plastic molded articles. A

While the invention lies in the use of a solvent plasticizer with apara-tertiary alkyl phenoxy ethanol other ingredients ordinarily used inplastic compositions may be used, such as fillers, pigments, dyes,stabilizers, etc.

The herein described compositions of matter may be used to form sheetsor films or coating compositions, including varnishes and lacquers, ormolded products, such as buttons, combs, electric plugs, fountain pens,telephone equipment,

etc.

Thus, the present invention has described a new and useful celluloseacetate composition in which certain phenoxy ethanols may be substitutedfor a part of the solvent plasticizers formerly used. The compositionhas good flow at molding temperatures and desirable hardness at ordinarytemperatures but nonbrittle.

What I claimand desire to protect by Letters Patent is: 1

I 1. A plastic composition comprising from about 40% to about 70% byweight of cellulose acetate and from about 60% to about 30% by weight oftotal plasticizer, said plasticizer consisting essentially of ap-tertiary alkyl phenoxy ethanol and a solvent plasticizer in the weightratio of not more than 3:1. 2. A plastic composition comprising fromabout 40% to about 70% by weight of cellulose acetate and from about 60%to about 30% by weight of total plasticizer, said plasticizer consistingessentially of p-tertiary butyl phenoxy acetate, from about asvaosoacetate and from about 60% to about 30% by weight of total plastioizer,said plasticlzer consisting essentially of p-tertiary amyl phenoxyethanol and a solvent plasticizer in the weight ratio of not more than3:1.

4. A plastic composition comprising from about 40% to about by weight ofcellulose acetate and from about 60% to about 30% by weight of totalplastlcizer, said plasticizer consisting essentially of a p'-tertiaryalkyl phenoxy ethanol and dimethyl phthalate in the weight ratio of notmore than 3:1.

5. A plastic composition comprising from about 40% to about 70% byweight of cellulose acetate having an acetic acid content of from 'about52% to about 57% and from about 60% to about 30% by weight of totalplasticizer, said total plasticlzer consisting essentially oi ap-tertiary alkyl phcnoxy ethanol and a solvent plasticizer in the weightratio of not more than 3:1.

6. A molded article comprising from about 40% to about 70% by weight ofcellulose acetate and from about 60% to about 30% by weight of totalplastlcizer, said plasticirer consisting essentially 01' a p-tertiaryalkyl phenoxy ethanol and a. solvent plasticizer in the weight ratio ofnot more than 3:1.

7. A plastic composition comprising from about 40% to about 70% byweight of cellulose acetate and from about 60% to about 30% by weight oftotal plasticizer, said plasticizer consisting essentially of p-tertiarybutyl phenoxy .ethyl' acetate and a solvent plasticizer in the weightratio of not more than 3:1.

8. A plastic composition comprising from about 40% to about 70% byweight of cellulose acetate, from about 60% to about 30% by weight oftotal plasticizer, a pigment and a stabilizer, said total plasticizerconsisting essentially of a p-tertiary alkyl phenoxy ethanol and asolvent plasticizer in the weight ratio of not more than 3:1.

9. A plastic composition comprising irom about 40% to about 70% byweight of cellulose 60% to about 30% by weight of total plasticizer anda dye, said total plasticizer consisting essentially of a p-tertiaryalkyl phenoxy ethanol and a solvent plasticizer in the weight ratio ofnot more than 3:1.

10. A plastic composition comprising from about 40% to about 70% byweight of cellulose acetate and-from about 60% to about 30% by weight oftotal plasticizer, said plasticizer consisting essentially of a materialselected from the group consisting of p-tertiary alkyl phenoxy ethanolsand p-tertiary alkyl phenoxy ethyl acetates and a solvent plasticizer inthe weight ratio 0! ct more than 3: 1.

n FRANK E. PIECE.

